my vote is it that fell out of the back of somebodys truck for it to actually fall out from underneath a vehicle you would have to break all of the bellhousing bolts all the torque converter bolts the transmission mount and the drive shafts not to mention a cross member or two the torque converter was probably resting in place and rolled away when tranny hit the ground being that its right there at the intersection i bet somebody did a full throttle take off and there she sits could very well have blown through a tailgate